JP7276335B2 - Manufacturing method of glass fine particle deposit - Google Patents

Description

The present disclosure relates to a method for manufacturing a glass particulate deposit.
This application claims priority based on Japanese Patent Application No. 2018-114363 filed on June 15, 2018, and incorporates all the content described in the application.

Patent Document 1 describes a method for producing a glass fine particle deposit using siloxane as a raw material for glass synthesis.
In addition, in Patent Document 2, when shifting to a mode in which glass particles are not deposited, instead of sealing gas, combustion gas is flowed to the sealing gas ejection nozzle, and in the combustion gas port, the combustion gas of the combustion gas port is switched to purge gas. is stated.
Furthermore, in Patent Document 3, when the supply of the glass raw material gas to the burner is zeroed, the raw material gas and the inert gas A are switched upstream of the MFC (Mass Flow Controller), and the gas from the MFC is switched to the burner. It describes switching from the exhaust side to the exhaust side, supplying inert gas B to the burner, and purging the source gas supply path with inert gases A and B.

Japanese Patent Application Laid-Open No. 2015-113259 Japanese Patent Application Laid-Open No. 2012-232875 Japanese Patent Application Laid-Open No. 2003-212554

The manufacturing method of the glass particulate deposit body of the present disclosure includes:
A method for producing a glass particle deposit, wherein siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. ,
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, the supply of the siloxane, which is the glass raw material, to the burner is stopped;
removing the glass particulate deposit from the reaction vessel;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
The supply of the combustion gas is stopped when the color resulting from the combustion of the siloxane gas is no longer observed in the flame from the burner.

Further, the method for manufacturing the glass particulate deposit body of the present disclosure includes:
A method for producing a glass particle deposit, wherein siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. ,
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, stopping the supply of the siloxane, which is the glass raw material, to the burner;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
After the glass particle deposit is heated for a certain period of time while being traversed relative to the burner by the flame formed by the combustion gas, the supply of the combustion gas is stopped.

1 is a configuration diagram showing one form of an apparatus for manufacturing a glass particulate deposit according to one aspect of the present disclosure; FIG.

[Problems to be Solved by the Present Disclosure]
In the case of manufacturing a glass particle deposit by the method described in Patent Document 1, liquid siloxane is gasified by a vaporizer and released from a burner, and glass particles are formed and deposited by an oxidation reaction. After manufacturing a good part of the glass particle deposit, the supply of siloxane gas to the burner is stopped, the glass particle deposit is taken out from the reaction vessel of the manufacturing apparatus, and another target member (starting rod) is newly prepared as described above. It is installed in a reaction vessel to manufacture a new glass fine particle deposit.
In the above case, siloxane may remain between the vaporizer and the gas discharge port of the burner after stopping the supply of siloxane gas to the burner and before manufacturing a new glass particle deposit. The remaining siloxane reacts with oxygen flowing back from the gas discharge port between the same positions, forming insufficiently oxidized silicon oxide (SiOx (X<2)) particles, or polymerizing ring-opened siloxanes to form a gel. It can form things. The above-mentioned silicon oxide (SiOx (X<2)) particles and gel-like substances clog the space between the gas outlet of the burner and the vaporizer, or are mixed into the newly produced glass fine particle deposition layer. , causing product defects.

Therefore, an object of the present disclosure is to provide a method for producing a high-quality glass fine particle deposit when siloxane is used as a raw material for glass synthesis.

[Effect of the present disclosure]
According to the present disclosure, when siloxane is used as a raw material for glass synthesis, a high-quality glass particle deposit can be produced.

[Description of Embodiments of the Present Disclosure]
First, the contents of the embodiments of the present disclosure will be listed and described.
A method for manufacturing a glass particulate deposit according to one aspect of the present disclosure includes:
(1) A method for producing a glass particle deposit, in which siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. and
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, the supply of the siloxane, which is the glass raw material, to the burner is stopped;
removing the glass particulate deposit from the reaction vessel;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
The supply of the combustion gas is stopped when the color resulting from the combustion of the siloxane gas is no longer observed in the flame from the burner.
According to this configuration, it is possible to prevent gaseous siloxane from remaining in the source gas port extending from the vaporizer to the burner after stopping the supply of siloxane. As a result, it is possible to manufacture a high-quality glass particle deposit.

A method for manufacturing a glass particulate deposit according to one aspect of the present disclosure includes:
(2) A method for producing a glass particle deposit, in which siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. and
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, stopping the supply of the siloxane, which is the glass raw material, to the burner;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
After the glass particle deposit is heated for a certain period of time while being traversed relative to the burner by the flame formed by the combustion gas, the supply of the combustion gas is stopped.
According to this configuration, it is possible to prevent gaseous siloxane from remaining in the source gas port extending from the vaporizer to the burner after stopping the supply of siloxane. As a result, it is possible to manufacture a high-quality glass particle deposit.

The method for producing the glass particle deposit according to (1) or (2) includes:
(3) It is preferable to continue purging the raw material gas port from the vaporizer to the burner during the period from the production of the glass particle deposit to the start of production of the next glass particle deposit. .
According to this configuration, from the time when the supply of siloxane is stopped to the time when a new glass particle deposit is manufactured, oxygen is prevented from being mixed into the raw material gas port from the gas discharge port of the burner due to backflow, and the insufficiently oxidized silicon oxide is prevented. It can prevent the formation of (SiOx (X<2)) particles and the polymerization of ring-opened siloxanes to form a gel.

The method for producing the glass particle deposit according to (1) or (2) includes:
(4) When producing a good portion of the glass fine particle deposited body, a carrier gas, which is an inert gas, was used to turn the siloxane into a gaseous state in the vaporizer, and the supply of the siloxane gas to the burner was stopped. After that, it is preferable to perform the purge to the source gas port by continuing to flow the carrier gas.
According to this configuration, there is no need to provide an additional inert gas supply mechanism for the purge, and the already provided carrier gas supply mechanism can be used as it is, thereby simplifying the apparatus configuration.

The method for producing a glass particle deposit according to any one of (1) to (4) includes:
(5) It is preferable to use nitrogen as the inert gas.
According to this configuration, by using inexpensive nitrogen as the inert gas, the glass particle deposit can be manufactured at low cost.

The method for producing a glass particle deposit according to any one of (1) to (5) includes:
(6) It is preferable that a pipe between the vaporizer and the burner is made of a material containing metal.
When a material containing metal is piped between the vaporizer and the burner, gaseous siloxane remaining in the pipe is more likely to be oxidized and gelated. Problems can be effectively prevented even in a device that is piped with a material containing metal, which is likely to cause problems. In addition, if the piping is made of a material containing metal, it can be heated at a high temperature.

The method for producing a glass particle deposit according to any one of (1) to (6) includes:
(7) It is preferable to heat the piping between the vaporizer and the burner to a temperature equal to or higher than the boiling point of siloxane.
According to this configuration, it is possible to prevent the remaining siloxane gas from cooling and liquefying.

[Details of the embodiment of the present disclosure]
[Overview of equipment used, etc.]
Hereinafter, an example of an embodiment of a method for manufacturing a glass particle deposit according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of an apparatus 1 for manufacturing a glass particle deposit (hereinafter also referred to as "glass particle deposit manufacturing apparatus" or "deposition manufacturing apparatus") of the present embodiment. The deposited body manufacturing apparatus 1 includes a reaction vessel 2, an elevating and rotating device 3, a siloxane supply tank 21, a carrier gas supply device 31, a combustion gas supply device 32, a burner 22 for producing glass microparticles, and operation of each part. and a control unit 5 for controlling the

The reaction vessel 2 is a vessel in which the glass particle deposit M is formed, and has an exhaust pipe 12 attached to the side of the vessel.

The elevating/rotating device 3 is a device for elevating and rotating the glass fine particle deposit M via the supporting rod 10 and the starting rod 11 . The lifting/rotating device 3 lifts and rotates the glass fine particle deposit M based on a control signal transmitted from the control unit 5 .

The support rod 10 is arranged to pass through a through hole formed in the upper wall of the reaction vessel 2, and a starting rod 11 is provided at one end (lower end in FIG. 1) arranged inside the reaction vessel 2. is installed. The support rod 10 is gripped by the lifting and rotating device 3 at the other end (upper end in FIG. 1).

A starting rod 11 is a rod on which glass particles 30 are deposited and is attached to the support rod 10 .

The exhaust pipe 12 is a pipe for discharging the glass particles 30 that have not adhered to the starting rod 11 and the glass particle deposit M to the outside of the reaction vessel 2 .

The burner 22 is supplied with siloxane gas, seal gas (not shown), and combustion gas.
Siloxane gas is obtained by mixing the liquid siloxane 23 sent from the siloxane supply tank 21 through the MFC 25 with the carrier gas in the vaporizer 24 . Specifically, in the vaporizer 24, the siloxane gas is generated by dropping the liquid siloxane 23 into the carrier gas jetted at high speed. A carrier gas is supplied from a carrier gas supply device 31 to the vaporizer 24 .
Combustion gas is supplied to the burner 22 from a combustion gas supply device 32 .

The MFC 25 is a device that controls the amount of liquid siloxane 23 supplied from the siloxane supply tank 21 and supplies it to the vaporizer 24 via the supply pipe 26 . The MFC 25 controls the amount of liquid siloxane 23 supplied to the vaporizer 24 based on control signals sent from the controller 5 .
The liquid siloxane 23 is supplied from the siloxane supply tank 21 to the MFC 25 by pressurization with an inert gas or by a pump. Helium is preferably used as the inert gas for pumping. Since helium does not easily dissolve in liquid siloxane, it is possible to prevent fluctuation errors in the supply amount due to vaporization of dissolved gaseous components (generation of bubbles).

The supply pipe 26 is a pipe for guiding the liquid siloxane 23 whose supply amount is controlled by the MFC 25 to the vaporizer 24 . The supply pipe 26 preferably has a function of heating the liquid siloxane 23 so that the liquid siloxane 23 can be easily vaporized in the vaporizer 24 . The function of heating the liquid siloxane 23 in the supply pipe 26 can be imparted by, for example, winding a tape heater 28 as a heating element around the outer circumference of the supply pipe 26 . When the tape heater 28 is energized, the supply pipe 26 is heated, and the temperature of the liquid siloxane 23 supplied to the vaporizer 24 can be brought close to a temperature suitable for vaporization in advance. For example, if the liquid siloxane 23 is octamethylcyclotetrasiloxane (OMCTS), it is preferable to raise the temperature to 150-170°C, which is slightly lower than the normal boiling point of OMCTS, 175°C.

The burner 22 oxidizes the siloxane gas obtained in the vaporizer 24 in a flame to generate glass microparticles 30, and the generated glass microparticles 30 are sprayed onto the starting rod 11 and deposited.
Siloxane is present in a gaseous state between the vaporizer 24 and the burner 22. At this time, the function of heating between the vaporizer 24 and the burner 22 is provided so that the siloxane gas does not cool and liquefy. It is preferable to have That is, like the supply pipe 26 , it is preferable that a tape heater 28 that is a heating element is wound around the outer circumference of the pipe between the vaporizer 24 and the burner 22 and part of the outer circumference of the burner 22 . When the tape heater 28 is energized, the pipe between the vaporizer 24 and the burner 22 and the burner 22 are heated, and liquefaction of the siloxane gas can be prevented. For example, if the liquid siloxane 23 is OMCTS, the temperature may be raised to 175 to 200°C, which is higher than the normal boiling point of OMCTS, 175°C.
As the burner 22 for ejecting siloxane gas or combustion gas, for example, one having a cylindrical multi-nozzle (outlet) structure or one having a linear multi-nozzle structure is used.

The control unit 5 controls each operation of the lifting and rotating device 3, the MFC 25, and the like. The control unit 5 transmits a control signal for controlling the lifting speed and rotation speed of the glass fine particle deposit M to the lifting/rotating device 3 . Further, the control unit 5 transmits a control signal for controlling the supply amount of the liquid siloxane 23 supplied to the vaporization device 24 to the MFC 25 .

[Deposition process]
Glass particles are deposited by an OVD method (external deposition method) to manufacture a glass particle deposit M. As shown in FIG. First, as shown in FIG. 1, a supporting rod 10 is attached to the lifting/rotating device 3, and a starting rod 11 is attached to the lower end of the supporting rod 10. Then, a part of the starting rod 11 and the supporting rod 10 is placed in the reaction vessel. Pay within 2.

Subsequently, the MFC 25 supplies the raw material liquid siloxane 23 to the vaporizer 24 while controlling the supply amount based on the control signal sent from the control unit 5 .

The glass microparticles 30 are generated by oxidizing the siloxane gas in the combustion gas flame.
Then, the burner 22 continuously deposits the glass particles 30 generated within the flame on the starting rod 11 that rotates and moves up and down.

The lifting/rotating device 3 lifts and rotates the starting rod 11 and the glass fine particle deposits M deposited on the starting rod 11 based on a control signal from the controller 5 .

Although the siloxane used as a glass raw material in the present embodiment is not particularly limited, cyclic siloxanes are preferable in that they are easily available industrially and easy to store and handle, and among them, OMCTS is more preferable.
The carrier gas and seal gas used in this embodiment are not particularly limited as long as they are inert gases, but examples thereof include helium gas, argon gas, nitrogen gas, etc. Nitrogen gas is preferred because it is inexpensive.
The combustion gas used in the present embodiment is not particularly limited as long as it can form a flame and contains oxygen for oxidizing siloxane, but oxyhydrogen gas is preferred. Oxyhydrogen gas is a mixture of hydrogen (combustible gas) and oxygen (combustible gas). It should be noted that when hydrogen and oxygen are separately supplied to the burner 22, both hydrogen and oxygen are included in the combustion gas of the present disclosure.

Although the OVD (Outside Vapor Deposition) method has been described as an example of the deposition process shown above, the present invention is not limited to the OVD method. Similar to the OVD method, the present invention can also be applied to a method of depositing glass from a glass raw material using an oxidation reaction, such as a VAD (Vapor-phase Axial Deposition) method, an MMD (Multiburner Multilayer Deposition) method, and the like. be.

[Process after completion of deposition process]
After producing a good part of the glass particle deposit M in the above deposition step, the supply of siloxane gas to the burner 22 is stopped, and the glass particle deposit M is taken out from the reaction vessel 2 of the deposition body manufacturing apparatus 1 . Then, another target member (starting rod 11) is newly installed in the reaction vessel 2, and a new glass particle deposited body M is manufactured.
However, as described above, if the siloxane gas remains in the raw material gas port, it causes defective products.
Therefore, in this embodiment, the siloxane gas is prevented from remaining in the source gas port from the vaporizer 24 to the burner 22 .
In this specification, the good part is the part of the glass particle deposit that can be used as a product such as an optical fiber.

Specifically, the steps of the following procedures are performed.
A1) After producing a good portion of the glass particle deposit M, while continuing to supply combustion gas to the burner 22, the supply of siloxane, which is a raw material for glass, to the burner 22 is stopped.
A2) Take out the glass fine particle deposit M from the reaction vessel 2 .
A3) Purging by flowing an inert gas through the source gas port from the vaporizer 24 to the burner 22 .
A4) Stop the supply of the combustion gas when the flame from the burner 22 is no longer colored due to the combustion of the siloxane gas.

As a method for stopping the supply of siloxane to the burner 22 in the above step A1), even if the supply of liquid siloxane from the MFC 25 to the vaporizer 24 is stopped, the supply of liquid siloxane from the siloxane supply tank 21 to the MFC 25 is stopped. may be stopped. Preferably, however, the supply of liquid siloxane from siloxane supply tank 21 to MFC 25 is stopped.
In the above step A1), the supply of the combustion gas to the burner 22 is continued even after the good portion of the glass particulate deposit M is produced.

In the above step A2), the glass particle deposit M is taken out from the reaction vessel 2, but the supply of the combustion gas to the burner 22 is continued even at this time. At this time, even if the supply of siloxane to the burner 22 is stopped in step A1), siloxane is released from the burner 22 because some siloxane remains.

The specific method of purging by flowing an inert gas in step A3) is not particularly limited, but the carrier gas (inert gas) is continuously supplied from the carrier gas supply device 31 to the vaporization device 24. is preferred. According to this aspect, there is no need to provide an additional inert gas supply mechanism for purging, and the already provided carrier gas supply mechanism can be used as it is, thereby simplifying the apparatus configuration.

In step A4) above, the presence or absence of color due to combustion of siloxane gas in the flame from the burner 22 is checked. When siloxane burns, the flame appears white or orange. On the other hand, when oxyhydrogen gas is used as combustion gas and only oxyhydrogen gas is burned, the flame exhibits a pale blue color. Therefore, when the flame from the burner 22 ceases to be white or orange and becomes only pale blue, it can be judged that the siloxane gas remaining in the piping has been exhausted. After that, the supply of combustion gas is stopped.

After the production of the glass particle deposit M, it is preferable to continue purging the source gas port from the vaporizer 24 to the burner 22 until the production of the next glass particle deposit M is newly started. With this aspect, it is possible to prevent oxygen from flowing back from the gas discharge port of the burner 22 to the raw material gas port after stopping the supply of siloxane until manufacturing a new glass particle deposit.

Further, in the apparatus used in this embodiment, the piping between the vaporizer 24 and the burner 22 may be made of a material containing metal. In general, siloxane tends to be oxidized and gelled by the catalytic action of the metal when it is in an environment in which it comes into contact with the metal. However, in this embodiment, siloxane is effectively discharged from the pipe between the vaporizer and the burner, so even if the pipe is made of a material containing metal, the above problems do not occur. Also, if the pipe is made of a material containing metal, it can be heated at a high temperature.

Further, in the apparatus used in this embodiment, the burner 22 may have a mechanism for retreating the glass particle deposit M in the radial direction as the glass particle deposit M grows. At least part of the supply pipe 26 between the vaporizer 24 and the MFC 25 may be made of a flexible material such as fluororesin.

The glass fine particle deposit M produced in this embodiment is then dehydrated and sintered to make the glass transparent, thereby obtaining a glass base material. The obtained glass base material has high quality such as extremely few air bubbles.

[Modified Example of Process After Completion of Deposition Process]
The steps after the deposition step are not limited to the steps including the above steps A1) to A4) (hereinafter also referred to as “step A”). Process B, which is a modification of process A and can be performed in place of process A, will be described below.

In step A, after producing a good portion of the glass particle deposit M in the deposition step, the supply of siloxane gas to the burner 22 is stopped, and the glass particle deposit M is taken out from the reaction vessel 2 of the deposit manufacturing apparatus 1, Although the combustion gas was flowed until the siloxane remaining in the raw material gas port was exhausted, the timing of taking out the glass particle deposit M from the reaction vessel 2 is not particularly limited. Step B is a step in which the glass particle deposit M is advanced without being taken out of the reaction vessel 2 until the supply of the combustion gas to the burner 22 is stopped. However, if siloxane gas remains in the raw material gas port, a gel-like substance adheres to the manufactured glass fine particle deposit M, causing the product to become defective. After that, the combustion gas is allowed to flow for a certain period of time so that the surface of the deposited glass fine particle deposit is roasted.

In the process B, specifically, the process of the following procedures is performed.
B1) After producing a good portion of the glass particle deposit M, while continuing to supply the combustion gas to the burner 22, the supply of siloxane, which is a raw material for glass, to the burner 22 is stopped.
B2) Purging by flowing an inert gas through the source gas port from the vaporizer 24 to the burner 22 .
B3) When the supply of combustion gas is continued for a certain period of time, the supply of combustion gas is stopped.
B4) Take out the glass particle deposit M from the reaction vessel 2 .

As a method for stopping the supply of siloxane to the burner 22 in the step B1), as in the step A1), even if the supply of liquid siloxane from the MFC 25 to the vaporizer 24 is stopped, the siloxane supply tank 21 Although the supply of liquid siloxane to the MFC 25 may be stopped, it is preferable to stop the supply of liquid siloxane from the siloxane supply tank 21 to the MFC.
In the step B1), as in the step A1), the combustion gas is continuously supplied to the burner 22 even after the good portion of the fine glass particle deposit M is produced.

Even after the step B1), the supply of combustion gas to the burner 22 is continued without removing the glass particle deposit M from the reaction vessel 2 . At this time, even if the supply of siloxane to the burner 22 is stopped in step B1), siloxane is released from the burner 22 because some siloxane remains.

The specific method of purging by flowing an inert gas in the step B2) is not particularly limited as in the step A3), but the carrier gas (inert gas) is preferably continued. According to this aspect, there is no need to provide an additional inert gas supply mechanism for purging, and the already provided carrier gas supply mechanism can be used as it is, thereby simplifying the apparatus configuration.

In step B3), the combustion gas is continuously supplied for a certain period of time, and after heating the glass particle deposit for a certain period of time while traversing the glass particulate deposit relative to the burner by the flame formed by the combustion gas, the supply of the combustion gas is stopped. Stop. This fixed period of time includes the time for exhausting the siloxane gas remaining in the raw material port and the time for burning the surface of the deposited glass fine particle deposit thereafter. As for the time to completely release the siloxane gas, as described above, the presence or absence of color due to the combustion of the siloxane gas may be checked. good.

Moreover, it is preferable that the predetermined period of time is 3 minutes or more and 1 hour or less. If the time is less than 3 minutes, the siloxane gas may not be completely discharged, or the gel-like component adhering to the surface may not be blown off sufficiently. In addition, if it is allowed to flow for one hour, the siloxane gas can be completely discharged, and it is sufficient to blow off the gel-like components adhered to the surface. Work efficiency also deteriorates.

Further, it is preferable to adjust the flow rate of the combustion gas and the like so that the temperature of the glass particulate deposit in step B3) is 700° C. or higher and 1200° C. or lower. If the temperature is 700° C. or higher, it is possible to blow away the gel-like component adhered to the surface. If the temperature is higher than 1200° C., the glass particle deposit may shrink or be sintered.

After completion of the step B3), the step B4) is performed. After that, as in the above step A, it is preferable to continue purging the source gas port from the vaporizer 24 to the burner 22 until the production of the next glass particle deposit M is newly started. With this aspect, it is possible to prevent oxygen from flowing back from the gas discharge port of the burner 22 to the source gas port from the time when the supply of siloxane is stopped to the time when a new glass particle deposit is produced.

Also in the apparatus used in this case, the piping between the vaporizer 24 and the burner 22 may be made of a material containing metal.

Also in the apparatus used in this case, the burner 22 may be a mechanism for retreating the glass particle deposit M in the radial direction according to the growth of the glass particle deposit M. At least part of the supply pipe 26 may be made of a flexible material such as fluororesin.

The glass fine particle deposited body M manufactured by performing the step B instead of the step A is then dehydrated and sintered in the same manner as in the step A to make the glass transparent, thereby obtaining a glass base material. The obtained glass base material has high quality such as extremely few air bubbles.

The present invention is not limited to these exemplifications, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1: Deposit manufacturing device 2: Reaction vessel 3: Elevating and rotating device 5: Control part 10: Support rod 11: Starting rod 12: Exhaust pipe 21: Siloxane supply device 22: Burner 23: Liquid siloxane 24: Vaporizer 25: MFC
26: Supply pipe 28: Tape heater 30: Glass particles 31: Carrier gas supply device 32: Combustion gas supply device M: Glass particle deposit

Claims (7)

A method for producing a glass particle deposit, wherein siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. ,
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, the supply of the siloxane, which is the glass raw material, to the burner is stopped;
removing the glass particulate deposit from the reaction vessel;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
A method for producing a glass particle deposit, wherein the supply of the combustion gas is stopped when the color resulting from the combustion of the siloxane gas is no longer observed in the flame from the burner. A method for producing a glass particle deposit, wherein siloxane is used as a glass raw material, and a siloxane gas gasified by a vaporizer and a combustion gas are emitted from a burner and burned to form a glass particle deposit in a reaction vessel. ,
After producing a good portion of the glass particulate deposit, while continuing to supply the combustion gas to the burner, stopping the supply of the siloxane, which is the glass raw material, to the burner;
Purging by flowing an inert gas through the raw material gas port from the vaporizer to the burner,
After heating the glass particle deposit for a certain period of time while traversing the glass particle deposit relative to the burner with the flame formed by the combustion gas, the supply of the combustion gas is stopped.
A method for producing a glass fine particle deposit. 2. The purge is continued to the source gas port extending from the vaporizer to the burner even after the production of the glass particle deposit and until the production of the next glass particle deposit is newly started. Item 3. A method for producing a glass particle deposit according to item 2. When producing a good part of the glass particle deposit, a carrier gas, which is an inert gas, is used to turn the siloxane into a gaseous state in the vaporizer, and even after stopping the supply of the siloxane gas to the burner, 3. The method for producing a glass particulate deposit according to claim 1, wherein said purge to said raw material gas port is performed by continuing to flow said carrier gas. 5. The method for producing a glass particle deposit according to any one of claims 1 to 4, wherein nitrogen is used as the inert gas. 6. The method for producing a glass particulate deposit according to any one of claims 1 to 5, wherein a pipe between said vaporizer and said burner is made of a material containing metal. 7. The method for producing a glass particle deposit according to claim 1, wherein a pipe between said vaporizer and said burner is heated to a temperature equal to or higher than the boiling point of siloxane.

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